Metal and its manufacture



A. PACZ. METAL AND ITS MANUFACTURE. APPLlCATlON FILED FEB. 20. 1917.

Patented Mar. 21, 1922.

IAIGAQQ.

INYENTUR 55253. 1 .552 W ,OQAM .His .A'z'z'anzvmx bring into intimate ALADAR PACZ, 0F CLEVELAND,

OHIO, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A

CORPORATION OF NEW YORK.

METAL am) m's MANUFACTURE Specification of Letters Patent.

Patented lvllar. 21, 1922.

Application filed February 20, 1917. Serial No. 149,915.

T 0 all whom it mag/concern:

Be it known that I, ALADAR PACZ, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga, State of Ohio, have invented certain new and useful Improvements in Metals and Their Manufacture, of which the following is a specification.

The object of my invention is to produce tungsten metal which will retain to a much higher degree than heretofore its original properties after being subjected to high temperatures. In the case of incandescent lamp filaments, the high temperatures at which they are run have caused them to elongate and sag between their supports. This is especially noticeable in coiled filaments, and in gas filled lamps this tends to reduce the efficiency of the lamp on account of the increased cooling effect on the filament. By means of my invention the sagging is sub stantially eliminated and offsetting of the filament is substantially prevented, during a normal or commercially useful life of the lamp.

In the preferred form of my invention T association with tungsten a material which will have the desired influence upon the grain growth of the metal. I precipitate, simultaneously, compounds from which the metal is to bedirectly reduced with the material or compound which 4 is to accomplish the desired result. The material after precipitation will remain in intimate association with the metal even after the same has been reduced by the ordinary means, i. e., reducing gases. During the subsequent formation of the metal into ingots or bars, the material should be such that it will be removed as by volatilization. A material should be used which will have a fairly high volatilization point which is preferably somewhat lower than the sintering point of the metal.

Considering my invention from the physical standpoint, the presence of the material has an influence on the grain growth of the metal. When the metal reaches the temperature at which extensive grain growth would ordinarily take place, the presence of this material the tungsten particles has a marked effect on size of the tungsten grains,

the shape and The ingot of tungsten thus produced, whether it be due to the fact that the grains intimately associated with have not reached the equilibrium grain size or to other causes, is particularly susceptible to grain growth 'during subsequent heat treatments.

The probable reason why filaments made according to my invention do not sag, is that the structure is comparatively coarse grained. The coarse grained filament produced by means of my invention does not ofiset so as to cut short the life of the lamp appreciably.

As hereinbeforestated, the material which Is intimately incorporated with the metal should be such that it will be volatilized out. after the metal has reached the temperature of rapid grain growth. Tungsten above 1500 C. shows rapid grain growth, and I may use silica, or compounds containing it, as the material, incorporated very intimately as heretofore explained. By the time the tungsten has reached the sintering temperature .the silica and the compounds containing it are volatilized. out.

Tn order to comply fully with the requirements of the patent statutes, I will now describe one method or process embodying my invention and also modifications thereof. However, it is to be understood that the scope of my invention is such that many changes and substitutions will readily suggest themselves to those skilled in the art, and, as indicated, in the appended claims, are to be considered as forming part thereof.

A fusion of materials is first made which is quite similar to that disclosed in my Pat- Number 1,299,017 issued April 1, 1919. 1400 grams of commercial tungstic acid, 620 grams commercial sodium carbonate, 620 grams commercial potassium carbonate, and 300 grams commercial sodium nitrate are mixed with water to a paste. I have found that half or more of the potassium carbonate may be replaced by sodium carbonate without afiecting the results, the object being to obtain a good fusion. This paste is dried on a hot plate and fused with a torch for about fifteen minutes, after which the fusion is dissolved in water, filtered and diluted to about six liters. This we will term solution A.

A mixture is then made of 180 grams com- 'mercial silicic acid,,620 grams commerclal. K 00 and 150 grams commercial NaNO jzwith Water to a paste which is dried and fused. The object is to produce a silicate which will be readily incorporated with the tungstic acid in the subsequent portion of the process. An alkaline silicate such as produced b the s ecific example given is readily solu 1e and efficacious for this purpose. The fusion is dissolved in water, filtered and diluted to 5 liters. This maybe termed solution B.

About 250 cubic centimeters of solution B are added to 3 liters of solution A. The whole solution is then boiled with steam and poured into a boiling solution containing about 1500 cubic centimeters of HCl and 1500' cubic centimeters of H 0, preferably through a funnel. The precipitate is allowed to settle, the liquid decanted, and the precipitate separated by filtration. The precipitate is then washed with hot H O until the filtrate becomes milky. The precipitate is then dried and ignited in a quartz dish.-

It is reduced in hydrogen in boats, each boat containing about 100 grams. The metal thus produced may be termed metal The metal A may be pressed up and sintered to produce tungsten slugs which may be drawn into filaments having the non-sag and other characteristics hereinbefore described. I prefer, however, in order to obtain greater uniformity of product to continue the operation as follows: V

About 1200 grams of metal A are mixed with about 1200 grams of the oxide from which metal A was reduced, the mixture being very intimate and being performed preferably in a tumbling mill. The mixture is then reduced as before although 150 gram charges may be here used. The metal thus produced may be termed metal B. It is then sieved, pressed into ingots and sintered in the usual way as set forth in the Coolidge Patent No. 1,082,933.

As a modification of the above described process, solution B may be added directly to the fusion from which solution A is made. This is preferably done by utilizing the proper proportion as heretofore stated of solution B in making the paste which is dried and fused and dissolved to form solution A.

The metal obtained from the first method above described I have called 218, a purely arbitrary name. I have produced a metal differing in appearance and physicalmetal by adding chemically pure characteristics from 218 a solution of boric acid to O evaporatin drying igniting and reduciiig. The m etal thus produced when made into wire is not superior to 218 in non-sagging or non-offsetting characteristics,

but a combination of this method with that for producing 218 in which the WO from the latter is mixed with that from the former produces a metal which I term Z and which is efiicacious in the production of nonsagging and non-oil'setting filaments. To

produce this metal one method which I have practiced is to mix 1 kilogram of the tungstic oxide from which metal A is reduced in the 218 process with a solution of 12.5 grams fused B 0 in 500 cubic centimeters of water. This mixture is evaporated, dried, ignited and reduced. The resulting metal is blacker than 218, flows more readily and possesses at least one-third larger volume than 218 although reduced under exactly the same conditions.

The tungsten ingots produced according to my invention usually have fine grains, as for example, between 2500 and 6500 grains per square millimeter. In the case of the 218 ingots analyses have shown that the percentage of non-metallic material is below two-tenths of one per cent and in many cases below one-tenth and even one-twentieth of one per cent.

When the tungsten metal produced by any of the methods above described is to be made into a filamentary body, the method described in the Coolidge Patent No. 1,082,? 933 for drawing or otherwise working down the ingots is practiced. 'Where the wire is to be used at high temperatures such as in incandescent electric lamps it should be given a preliminary heat treatment or aging. This helps to secure the non-sag characteristics of the wire made according to my invention. One procedure followed with good results with the ordinary 110l15 volts lamps was to run at 30 volts for 2 minutes and then at steps of 5 volts each for two minutes up to volts. After this the wire was run at 115% voltage for 15 minutes.

In the accompanying drawing I have shown, in elevation, lamps, the filaments of which are made according to my invention. Figs. 1, 2 and 3 are front elevations of these lamps, while Figs. 4 and 5 are partial side elevations showing the filaments and supports. All of these lamps may be of ordinary voltage, i. e. 110 volts, and of any of the ordinarily used wattages; The lamps shown in Fig. 1 and Fig. 2 are of the gasfilled type disclosed in the Langmuir Patent No. 1,180,159, and have coiled filaments 11 and 12. The lamp shown "in Fig. 3 is a vacuum lamp having the coiled filament 13. The support 14-. is provided for the single loop filament 11 and the support 15 for the 100 watt lamps embodyshown in'Figs. 1 and 2 that substantially all of the saggm occurs during the aging of the lamp. This is when the lamp fi ament is given the heat treatment hereinbefore re ferred to. The sagging was greater in the case of the construction shown in Fig. 1 than -in that shown in Fig. 2 on account of the fact that in the latter there are more supports. In the construction shown in Fig. 1' in the case of 50 watt 115 volt lamps in which the filament was 1.62 mils in diameter and whichv was made by coiling on a mandrel of 5 mils diameter, the turns per inch originally ran from 421 to 430 and after aging the average decrease in the number of turns per inch was from 18 to 21L This was under In the case of the construction shown in Fig. 2 the decrease was from 1 to 6 turns. or under 2%. In the case of 100 watt 115 volt lamps. in which the filament diameter was 2.63 milsand the filament was shaped by coiling upon an 8 mil mandrel the number of turns per inch originally ran from 257 to 269. After aging, in the case of the construction shown in Fig. 1 the decrease in number of turns was from O to 10 or less than 5% and in the case of construction shown in Fig. 2 it was from 0 to 6 turns per .inch, or less than In one case, after total life of a 100 watt lamp, the number of turns decrease in the case of the construction shown in Fig. 1 was 12, while in the construction shown in Fig. 2 it was 4;.

VVhat I claim is:

1. The process of producing substantially non-sagging and non-offsetting tungsten filaments, which includes intimately associating finely divided tungsten and a material which volatilizes mainly at temperatures within the range of rapid grain growth of the tungsten and thereafter sintering the tungsten into a coherent body.

2. The process of producing substantially non-sagging and non-oltsetting tungsten filaments, which includes intimately associating finely divided tungsten and a material which volatilizes mainly at temperatures within the range of rapid grain growth of the tungsten, thereafter sintering the tungsten into an ingot, and working such ingot into filament form.

3. The process of producing substantially non-sagging and non-offsetting tungsten filaments. which consists in reducing a tungsten oxide intimately associated with a material which volatilizes mainly at temperatures within the range of rapid grain growth of the tungsten and thereafter producing a coherent body by sintering a compacted body of the product of such reduction.

4. The method of producing substantially non-sagging and no -offsetung tungsten filaments, which inclu es producing a coherent body of tungsten by sintering finely divided tungsten having intimately associated therewith a compound or compounds containing silicon and oxygen and volatilizing mainly by heating of rapid at temperatures within the range of rapid grain growth of the'tungsten.

5. The method of producing substantially non-sagging and non-offsetting tungsten fil aments. which includes produclng a coherent body of tungsten by sintering finelydiv ided tungsten having intimately associated therewith a compound or compounds containing silicon, oxygen and. an alkali metal, and volatilizing mainly at temperatures within the range of rapid grain growth of the tungsten.

6. The method of producing substantially non-sagging and non-offsetting tungsten filaments which includes producing a coherent body of tungsten by sintering finely divided tungsten having intimately associated therewith'a compound or compounds, containing silicon, oxygen and potassium, and volatilizing mainly at temperatures within the range of rapid grain growth of the tungsten.

7 The method of producing tungsten filaments, which includes producing an ingot finely divided tungsten having intimately associated therewith a compound or compounds, containing silicon and oxygen, and volatilizing mainly at temperatures within the range of rapid grain growth of the tungsten, and thereafter working said ingot down to filament form.

8. The method of producing tungsten filaments, which includes'producing an ingot by sintering finely divided tungsten having intimately associated therewith a compound or compounds, containing silicon, oxygen and an alkali metal, and volatilizing mainly at temperatures within the range of rapid grain growth of the tungsten and thereafter working said ingot down to filament form.

9. The method of producing tungsten filaments, which includes producing an ingot by sintering finely divided tungsten having intimately associated therewith a compound or compounds containing silicon, oxygen and potassium, and volatilizing mainly attemperatures within the range of rapid grain growth of the -tungsten,and thereafter working said ingot down to filament form.

10. The method of producing tungsten filaments, which includes reducing a tungsten oxide intimately associated with a compound or compounds containing silicon and oxyfilaments, which includes reducing a tungsten oxide intimately associated with a compound or compounds containing silicon, oxygen and an alkali metal, and volatilizing mainly at temperatures within the range grain growth of the tungsten, and

, tering a compacted body of the product of 13. The method filaments, which consists in reduclng a tungsuch reductio of produclng tungsten sten oxide intimately associated with a compound or compounds containing silicon the said ingot.

and oxygen and volatilizing mainly at temperatures within the range of'rapid grain growth of the tungsten, roducing an ingot by sintering a compacted body of the product of such reduction and working dowif 151. The method of producing tungsten filaments, which consists in reducing a tungsten oxide intimately associated with a compound or compounds containing. silicon, oxygen and an alkali metal and volatillz ing mainly at temperatures within the range of rapid grain growth of the tungsten. and producing an ingot by sintering a compacted body of the product of such reduction and working down the said ingot.

15. The method of producing tungsten filaments, which consists in reducing a tungsten oxide intimately associated with a compound or compounds containing silicon,

oxygen and potassium and volatilizing at temperatures within the range of rapid grain growth of the tungsten and producing an ingot by 'sintering a" compacted body of the product of such reduction and Working down the said ingot.

16. The process of producing substantially non-sagging and non-offsetting tungsten filaments, which includes intimately associating tungsten oxide and a material which volatilizes mainly at a temperature within the range of rapid grain growth of tungsten, reducing a portion of said oxide to metal, mixing said metal with another portion of said oxide, reduein ing the product oi: mentary form.

17. The process of producing substantially non-sagging and non-offsetting tungsten filaments, which includes preparing said reduction into filatungsten oxide intimately associated with an alkali metal and an oxide of silicon, reducing said tungsten oxide to metal, mixing said metal with another portion of said oxide, reducing said mixture, and working the product of said reduction into filamentary form.

I ments, which said mixture, and work-- 18. The process of producing substantially non-sagging and non-offsetting tungsten filaments, which includes preparing tungsten oxide intimately associated with potassium and an oxide of silicon, reducing a portion of said oxide to metal, makin a mixture of said metal and another portion of said oxide, reducing said mixture, and working the product of saidreduction into filamentary form.

19. The process of producing'substantially non-sagging and non-offsetting filaincludes precipitating a tungsten compound from a solution containing as constituents an alkali metal and a silicon oxide and reducing the precipitate substantially to tungsten metal.

20. T tially non-sagging and non-offsetting filaments, which includes sten compound from a solution containing as constituents an alkali metal and a silicon oxide, reducing the precipitate substantially to tungsten metal,-forming an ingot thereirom and workingthe same into filament orm.

,21. The process of producing substantially non-sagging and non-ofisetting filahe process of producing substanprecipitating a tang ments, which includes precipitating a tungsten compound from a solution containing as'constitue'nts potassium and a silicon oxide and reducing the precipitate substantially to tungsten metal. 22. The process of producing substantially non-sagging and non-offsettingfilaments, which includes precipitating a tungsten compound from a solution containing as constituents potassium and "a silicon oxide, reducing the precipitate substantially to tungsten, forming an ingot therefrom and working the same into filament form.

23'. A tungsten filament containing materially less than three-fourths of one per cent of non-metallic material and substantially free from sagging and ofl'setting during a normal or commercially useful hie.

24. A coiled tungsten filament containing materially less than -three fourths of one per cent of non-metallic material and substantially free from sagging and off-setting during a normal or commercially useful life.

made up mainly of grains of such size and contour as tov prevent substantial sagging and ofi-settin during a normal or commercially usefulli e for such a lamp or other device.

27. A filament for electric incandescent lamps or other devices, composed of tungsten containing less than three-fourths of ting during a normal or commercially useful life.

30. A drawn filament composed mainly of tungsten and capable of use in an electric incandescent lamp without substantial sagging' and'without substantial offsetting during a normal or commercially useful life.

31. A filamentary body composed substantially of tungsten and adapted to be mounted in an incandescent electric lamp and after it has been aged, capable of a normal or commercially useful life without substantial sagging and without substantial ofisetting.

32. A drawn tungsten wire adapted for use as an incandescent lamp filament and capable after aging, of a normal or com- 'mercially useful life without substantial sagging and without substantial offsetting.

In witness whereof, I have hereunto set my hand this 16th day of February, 1917.

ALADAR PACZ.

DESOLAHMER 1,410,499.Aladar Pace,

Cleveland, Ohio.

METAL AND I'rs MANUFACTURE.

Patent dated March 21, 1922. Disclaimer filed November 10, 1933, by the assignee, General Electric Company. Therefore enters this disclaimer to so much of the statement on lines 52 to 59 of page 2 of the printed patent specification as might imply or tend to imply that by addin a solution of boric acid to chemically pure W0 evaporating,

y g i n g and re ucing alone, it is possible to produce commercially useful non-sagging an non-offsetting tungsten filaments.

[Ofiiclal Gazette December 5, 1939.]

DISOLABMER Hereby enters this disclaimer of claims 23, 24, 28, 29,

patent.

METAL AND ITs MANUFACTURE. Patent Disclaimer filed June 16, 1938, by the assignee,

30, 31, and 32 of said And further disclaims from the scope of each of claims 25, 26, and 27 all filaments except filaments of the character therein described, a size and contour comparable to the grains grains of ance with the processes described in the s ecification at a hne 49, and page 2, lines 89 to 102. p p ge [Oflic'lal Gazette July 12, 1938.]

whichare made up mainly of of filamentsproduced in accord- 1, lme 89 to page 2, 

